Question 1 of 33

1. What is the name of the component marked as 'X' in the block diagram of AC drive?

Inverter

Rectifier

D.C bus

A.C motor

Question 1 of 33

Question 2 of 33

2. What is the purpose of JOG key in control panel of D.C drive?

Reverse the direction of motor

Stop the motor

Inching operation

Restart the motor

Question 2 of 33

Question 3 of 33

3. Which power modulator is used in the electric drive system?

Cyclo converters

Frequency multiplier

Phase sequence indicator

Servo controlled voltage stabilizer

Question 3 of 33

Question 4 of 33

4. How can the base speed of D.C shunt motor be increased by using D.C drive?

By increasing the supply voltage

By reducing the field current

By reducing the armature voltage

By increasing the field current

Question 4 of 33

Question 5 of 33

5. What is the main use of A.C drive?

High starting torque

Control stepless speed in motors

Interlocking system in industries

Group drive motors

Question 5 of 33

Question 6 of 33

6. What is the disadvantage of DC drive?

More expensive than AC drive for high capacity motor

Installation of DC drives is more complicated

More complex with a single power conversion

Not suitable for high speed operation

Question 6 of 33

Question 7 of 33

7. What is IGBT in VF drive?

Inverter switching device

Rectifier switching device

Field supply switching device

D.C bus switching device

Question 7 of 33

Question 8 of 33

8. Why are A.C drives mostly used in process plants?

Very high starting torque

Maintenance free long life

Robust in construction

Easy to operate

Question 8 of 33

Question 9 of 33

9. Which is the classification of drive according to dynamics and transients?

Automatic control drive

Intermittent duty drive

Variable position control drive

Short time duty drive

Question 9 of 33

Question 10 of 33

10. How can constant torque be obtained from armature and field controlled drives?

By reducing the armature current

By increasing the field current

By controlling the armature voltage

By reducing the field current

Question 10 of 33

Question 11 of 33

11. What is the purpose of PROG/DATA button in BOP of AC drive?

To store the entered data and factory stored data

To change the parameter setting

To display the data direction of rotation forward/REV

To display the data status of frequency and current

Question 11 of 33

Question 12 of 33

12. Which control system is used for Eddy current drives?

AC voltage controller

Rectifier controller

DC chopper controller

Slip controller

Question 12 of 33

Question 13 of 33

13. What is electric drive?

A machine converts mechanical energy into electrical

A device used as prime mover for generator

An electro mechanical device for controlling motor

A device converts A.C to D.C supply

Question 13 of 33

Question 14 of 33

14. Which is the correct sequence operation of key button in BOP of AC drive to change the direction of rotation?

Press ON → OFF → REV → ON

Press ON → REV → OFF → ON

Press OFF → REV → ON

Press ON → REV → ON

Question 14 of 33

Question 15 of 33

15. What is the advantage of AC drive compared to DC drive?

Requires less space

Fast response and wide speed range of control

Installation and running cost is less

Power circuit and control circuits are simple

Question 15 of 33

Question 16 of 33

16. What is the function of VSI drives?

Converts D.C to D.C

Converts D.C to A.C

Converts A.C to D.C

Converts A.C to A.C

Question 16 of 33

Question 17 of 33

17. What is the function of Field Supply Unit (FSU) in DC drive?

Provides a constant voltage to the field winding of motor

Produces required firing current to the firing circuit

Provides variable voltage to the field winding of motor

Provides a constant voltage to the armature of the motor

Question 17 of 33

Question 18 of 33

18. What is the function of IGBT in AC drive?

Stabilize the output voltage from the rectifier

Smoothening incoming A.C supply

Converts incoming A.C power into D.C power output

Controls the power delivered to the motor

Question 18 of 33

Question 19 of 33

19. What is the function of power controller in drive circuits?

It maintain the torque at low voltage conditions

It sounds an alarm in no load conditions

It detects the overloading condition of motor

It reduce motor current during transient operation

Question 19 of 33

Question 20 of 33

20. Which control system consumes very low power for motion control in AC and DC motors?

Field control

Voltage control

Armature control

Drives control

Question 20 of 33

Question 21 of 33

21. Which device controls the speed of A.C motor in A.C drive?

Microprocessor based electronic device

COMMS technology box

Field supply unit (FSU)

Speed feedback technology box

Question 21 of 33

Question 22 of 33

22. Which is proportional to the torque in D.C motor?

Terminal voltage

Armature current

Field current

Back e.m.f

Question 22 of 33

Question 23 of 33

23. What is the purpose of LCD on basic operator panel in D.C drive?

Display availability of supply

Display the speed

Monitor the parameter

Indicate the fault

Question 23 of 33

Question 24 of 33

24. What is the full form of B.O.P in D.C drive?

Bridge Operator Programme

Bridge Operation Panel

Basic Operational Panel

Basic Operation Programme

Question 24 of 33

Question 25 of 33

25. Which type of sensing unit is employed in drive systems?

Speed sensing

Opto coupler

Photo voltaic cell

Resistance temperature detector

Question 25 of 33

Question 26 of 33

26. Which is the application of single quadrant loads operating in first quadrant in drives?

Centrifugal pumps

Hoists

Elevators

Conveyors

Question 26 of 33

Question 27 of 33

27. Why is it necessary to keep V/F ratio constant in a drive?

Maintain the rated torque at all speeds

Maintain the rotor current minimum

Maintain the speed of motor constant

Keep the stator flux maximum

Question 27 of 33

Question 28 of 33

28. Why are A.C drives better suited for high speed operation?

Robust in construction

No brushes and commutation

High starting torque

Having lighter gauge winding

Question 28 of 33

Question 29 of 33

29. What is the purpose of LCD in Basic Operator Panel (BOP) in AC drive?

Indicate the incorrect operation of BOP

Monitor the parameter of AC drive

Indicate the display error in reading

Indicate the status of drive

Question 29 of 33

Question 30 of 33

30. Which type of machine in industries is provided with multi-motor electric drive?

Heavy duty electric drilling machine

Rolling machine

Shearing machine

Air Compressor

Question 30 of 33

Question 31 of 33

31. What is the reason for using shielded cable for connecting low level signal circuits in DC drives?

Eliminates the electrical interference

Protects from mechanical injuries

Easy for connection

Good appearance

Question 31 of 33

Question 32 of 33

32. Which drive is classified according to mode of operation?

Manual drive

Individual drive

Group drive

Continuous duty drive

Question 32 of 33

Question 33 of 33

33. What is the name of the characteristic curve in D.C drive?

Speed Vs torque characteristic

Speed Vs armature current characteristic

Torque Vs field current characteristic

Field current Vs armature current characteristic

Question 33 of 33